Awhile ago I posted a thread about some drivability issues I had with my Xplorer 400. I have since rebuilt the carb and it has taken care of my fuel consumption problems and it has really helped with how it drives and has alot more pep. The one issue I can't seem to shake is the choppiness at low speeds. From off idle to just about 1/4 throttle the engine justs seems choppy like it is missing. The plug isnt fouling out and is burning nice and not all sooty. Is it normal for a two stroke to have this choppiness to it? I took it on a ride last week and it ran excellent all day. It has alot of ***** for power but when cruising at under 20 mph it just seems a little erratic. Above that it is smooth as silk. I just bought another Polaris to add to my collection, a 2000 Sportsman 500. I really like how this one rides and the motor is super smooth. I do know one thing, that old 400 is a heck of alot faster than the 500, lol. Someone told me that crank seals on a two stroke can make it act erratic, but would that be through the whole rpm cycle? Everyone around here has four strokes so I cant get any knowledge about how a two stroke runs at low speeds.

Thanks,

Mike

 

Several things can cause bogging,erratic operation at low speed. The air screw can be a little toward the lean side or rich side. Normally around 1-2 turns out,but may take a little adjusting. You can also raise or lower the clip on the slide needle to see if helps on low end. Plus things like a worn float arm or float pin,float setting off,slight warping on reeds also. Jetting depends on altitude and temperature. Stock main jet was a 210,pilot was a 30 from seal level up to about 3000 ft or so. For a lot of the old farmers and ranchers down here that putted a lot, I had to drop the main jet to 190 or so along with lowering the slide needle. Your case me be exactly opposite,but these are some things you can experiment with.Plus if you installed an aftermarket carb kit check that the jets supplied are the same size as the old ones.

 

Thanks OPT,

This thing doesn't actually bog, just kinda choppy like its missing. Starts excellent, dont even have to choke it. Pops right off without more than a couple turns of the starter. When I went and got the carb kit, I found that 96 was its own year when it came to carb kits. I had to get one specifically for the 96 400L and made sure I checked the jets to make sure they matched what I had in the machine already. I had to get my magnifying reader out to read the numbers(because I'm getting old) but my main jet was a 210 and the pilot jet was a 30. The jet needle was a 6DH29. In the service manual it had a -3 behind it so I assume this was the setting the factory used for the clip because that is where mine was. I assume if I drop the clip down, it will pull the needle out sooner, making it richer on the low end. Not sure if richer is what I need but this thing isnt really bogging, it still is responsive, just acts like its not firing smoothly. I was always told that a lean condition causes missing. once the throttle gets past a certain point this thing is super smooth. I bought the 2000 Sportsman so the kids could ride it because I kinda want to keep the Xplorer for my riding and when I need to have a workhorse. I use it to plow snow and I do make alot of firewood in the fall and winter so it earns its keep with me so I want to keep the miles down on it but in the same time I want to be able to drive it smoothly around the campground in the summer.

P.S.
Is there anything about the 2000 Sportsman 500 that I should keep an eye on? The guy who had it before really babied it and was really a fanatic about changing the filters and fluids and washing it often. This thing still had the original tires on it and he put the rears on it before I bought it. It seems pretty dependable, but I just want to know if there are any weak points.

Thanks,

Mike

 

3rd position down on the needle is the stock position for the clip. This is the area where I'd experiment first on needle position to see if you can clear up the low speed choppy running. 2002 Sportsman 500 was a good machine.Major problem I had with it and the 2001 was creeping and hard shifting after they had some miles on them.Main cause of this was the brass washer and fiber washer wear on the one way bearing in the front clutch.Other than that if you maintain it properly it will last for many more years.The 500 was the most dependable engine Polaris had imo.

 

Well, I finally had time to play around with the clip on the slide needle on my Xplorer 400. I first dropped it (rich) one spot with no noticeable difference in driving. I then went up (lean) one slot past the stock setting and took it for a ride. It really smoothed out! I think there is just a slight choppiness just off of idle but I might be able to get rid of that with some adjustment of the air pilot screw. I dont want to move up another slot for fear of making it too lean so I will drive it a bit and check the plug to see how it is burning. I did notice the plug is slightly black so it may have been a touch rich.

Thanks OPT!

Mike

 

Change the sooty plug if you haven't already and open the air screw 1/4 turn and see how it does then. If you have to drop the needle to one spot leaner shouldn't hurt as I've had to do the same down here on slow poking farmers. Just depends on temp and altitude.Remember though as colder weather approaches they will run leaner.

 

Thanks OPT!

We took our Polaris Fourwheelers on a ride this weekend and everything worked great. I was very happy with the fuel mileage on our ride, it didnt seem to be a gas hog like it used to be. I let my daughter drive the Xplorer and she loved it. We rode with about 15 bikes, everything from brand new Rangers and Can-Ams to older Hondas and Yamahas. The three we have are the 96 Xplorer, the 2000 Sportsman and a 97 Yamaha Breeze. The Breeze just gets run around the campground and doesnt see a lot of trail riding even though it can easily do 30 to 35 mph. I just dont like the little ATVs on the trail.

Now I just have to replace the inner tie rods on Xplorer and Sportsman this winter.

Thanks again!

 

Good looking kids,but too many machines to have to keep up with... Glad the carb kit worked out for you.

 

If you ever do take the Breeze on the trails don't expect it to last long. My friends wore one out in no time.